Help with calibration

Easel
1

newbie here, so any help is greatly appreciated…I’m just getting started with a Sainsmart genmitsu 3800 pro. I can do some basic carvings, but I’m trying to create a box using the easel box app, but the parts don’t fit together. They’re 2/8th of an inch too big to fit together. Also, the depth (z axis) is going almost 3/8th of an inch too deep (which ruins the box top groove cut out).

In candle, I have the X,Y & Z axis all set to 800, and I do not currently have digital calipers, but I took a board and marked off inch marks with a ruler. When I put my drill bit on 1 mark and jog the machine 1 inch to the right, it moves exactly 1 inch. Same for the Y and Z axis. So I thought my machine was well calibrated, but when it goes to carve something, obviously it’s well off.

Any thoughts on what I may be doing wrong? thanks!

2
  • Measure over the largest span each axis can travel, this will reduce the backlash component.
  • With the router powered OFF, pull/push by hand on the bit. How much does it deflect?
  • Pockets will be undersized, outside will be oversized, this offset need to be compensated by playing with bit diameter value (Trial and error, but 2/8" (1/4") is a lot)
  • I assume the bit follow the correct path, as in “Outside cut” on the outside and “Inside cut” for the pocket.
3

thank you for the reply! Yes, when I measure across the entire X & Y axis almost 12 inches across it still measures very accurately, less than 1/8th of an inch off perhaps.

As for the bit deflecting, it does move a bit if I really push on it, however when I cut that last box, I had the feed speed set very low, 6 or 9 in per minute which was almost as slow as it can go. It does deflect at higher speeds, but I thought the lower feed speed would help correct for that.

To help correct, do I set the diameter value bigger or smaller?

thanks!

4

DOC will also effect deflection.
How deep per pass were you cutting?

5

easel has it set to 0.028 for the depth per pass.

what is “DOC”?

6

DOC is depth per pass.